CODEWITHSUNDEEP
phpclassfunctionrequire
Alex
Alex

Reputation: 67658

require_once() in a class

I noticed that if I declare a function inside a class method that has the same name as a outside function I get a error:

function a(){
  ...
}

class foo{
  public function init(){
    function a(){  // <- error
    ...    
    }
    ...
  }

}

this however would work:

function a(){
  ...
}

class foo{
  public static function a(){
    ...
  }
}

Can I include a set of functions that act as static methods for this class using require_once or something like that?

require_once('file.php'); after class foo{ doesn't work...

Upvotes: 5

Views: 5799

Answers (4)

Tgr
Tgr

Reputation: 28200

If your class structure allows, you can split the class into several different classes which are part of an inheritance chain:

class foo1 {
    public static function a() {}
}
class foo extends foo1 {
    public static function b() {}
}

Alternatively, you can use __callStatic() if you are willing to take the performance hit. (Requires PHP 5.3; though if you only need non-static methods, __call is available from 5.0.) Smarty 3 does this IIRC. 

class foo {
    private static $parts = array('A', 'B');
    public static __callStatic($name, $arguments) {
        foreach (self::$parts as $part) {
            if (method_exists($part, $name)) {
                return call_user_func_array(array($part, $name), $arguments);
            }
        }
        throw new Exception();
    }
}
class A {
    public static function a() {}
}
class B {
    public static function b() {}
}

PHP 5.4 will supposedly include traits, which are a more straightforward way of including external code in a class:

class foo {
    use A, B;
}
trait A {
    public static function a() {}
}
trait B {
    public static function b() {}
}

Upvotes: 1

Christopher
Christopher

Reputation: 31

Assuming not defining the second "a" method is not acceptable, you'll need to move it outside the init method.

It sounds like your require_once call is the problem (definitely should not be called inside the class). Could you post a full sample including your require_once call that isn't working ?

Upvotes: 1

Joost
Joost

Reputation: 10413

To answer the question: you should first check whether or not the function a has already been implemented by using function_exists:

class foo{
  public function init(){
    if(!function_exists('a')):
    function a(){  // <- will only be declared when it doesn't already exist
        ...    
    }
    endif;
    ...
  }

}

However, consider this as a very bad coding practice. It will get a mess pretty soon as you have no idea of what's going on exactly and what function will be used. I'd say you'd be better off using a subclass and require_once the appropriate subclass.

Upvotes: 1

mario
mario

Reputation: 145482

PHP allows to nest function declarations in others, but it doesn't actually have nested functions. They always end up in the global scope. So the a() that you define in your init method clashes with the already defined function a().

The static function a() is associated with the class namespace, even if it behaves like a function, not a method.

Invoking a require_once statement in a class definition is not possible. The PHP syntax does not allow for it. Class definitions are special scopes / language constructs, that only allow function or variable declarations within the immediate parsing level. - So PHP does not allow for that (classes and their methods must be declared at once, not assembled), and there are no really nice or advisable workarounds for what you want.

Upvotes: 3

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